Tankless water heater

[AlmightyJay]

I currently have a Navien tankless water system and have no major complaints at all. It has a recirculating pump and circulates the water throughout the day so we never have to wait more than 5-10 seconds for hot water at any tap within the house (2 storeys). It also has a LCD control panel on the unit which controls the temperature. I believe it goes up to a max of 140 degrees but we set it to 120 which is more than fine for our family.

The only thing that drives me nuts is the yearly maintenance service costs to perform a flush on the unit. It is a simple process but needs to be done by a professional, otherwise it voids the warranty. The cost for me is $349.

I tried calling around to see what various plumbers charge to perform a unit flush but none of the big plumbing companies in Calgary will touch the unit because it wasn't installed by them. Everyone says the same thing. It must be performed by the original installer.

This should be factored into the decision making process before you purchase one.

[photon]

Yeesh what happens if the original installer decides to switch to a new job? Or gets hit by a bus? No more unit flushes for you!

[redforever]

I have a Rinnai and would not recommend unless you put in a circulating pump. I am the second owner of my place of residence, and although only 5 years old, a circulating pump was not installed with the hot water heater. My place is fully developed up and down so it is not possible to install a circulating system now.

My laundry is on the second floor and it takes a long time for hot water to get there without a circulating pump. The new front load washing machines take very little water so I could never wash with warm or hot water.

I had a small 4 gallon water heater installed below the sink in my laundry room just so I could have warm or hot water for laundry purposes. That put me back around $1500.00.

[You Need a Thneed]

Originally Posted by puckedoff

I would like to install something to boost my hot water to a ridiculous temperature for baths/showers. Any plumbers out there know what kind of device I would need (Like an in-line tankless heater) but that accepts hot water as input?

Most shower knobs, have a physical stop that can be adjusted to allow for a higher percentage of hot water.

[FurnaceFace]

We've had a Rinnai for probably going on 10 years now. A big caveat off the bat is I’ve never officially done the math on savings. I did comparisons the first year and we were using less gas but haven’t gone in great detail.

Some observations:

We are two in the house therefore a hot water tank would sit idle a lot. That’s a big selling point of the on demand system, you’re not burning gas to heat the water in the tank during the day when you aren’t using it. If you have a larger family with more frequent demands then the savings are less.

You do need to wait for the water to get warm. Basically your flushing the line with the water sitting in the pipe and then the water that runs through the unit as it heats up. We don’t find it a massive issue. When we were looking at the system I read about a lady who hated it because she would give her kids a bath and want to warm up the water part way through and she would have to run the sink first to get hot water. That seemed a fairly specific example but it’s one.

Hot water forever. As the second shower-er with our tank system I’d sometimes run out if I took too long. There were also times where the washing machine got turned on and I’d lose some heat.

Our installer suggested if we didn’t need the space to leave the water tank in place. His reasoning was two fold: 1) the water in the tank would be around room temperature therefore it would take less energy to heat up 2) if there was ever an issue with the tankless system someone could easily hook up the gas line to the tank and we’d have hot water. Both ideas made sense to us.

With the current system we have run showers and dishwasher or washing machine at the same time with no issues. The trick is to let the gas co know you have put in an on demand system and have them install a larger meter. At first we had an issue where we would lose hot water as there wasn’t enough supply to the burners when it really needed to kick in once our tank was empty (see above).

For those who want scorching hot water there is a temp control on the tankless unit which I believe tops out at 140F. I think that is scalding temp.

We have never had any servicing for scaling and it was never discussed or brought up as a need. Our system runs fine.

[GP_Matt]

I loved the tankless system I had in my last house. The only issue we had was that the air intake was really sensitive so a few bugs on the screen would occasionally send an error code to the system and you had to reset it to restart the heater.
In my new house with a normal tank I find that the temperature isn't constant and drops over the course of the shower.

[Bean]

Originally Posted by AlmightyJay

The only thing that drives me nuts is the yearly maintenance service costs to perform a flush on the unit. It is a simple process but needs to be done by a professional, otherwise it voids the warranty. The cost for me is $349.

I tried calling around to see what various plumbers charge to perform a unit flush but none of the big plumbing companies in Calgary will touch the unit because it wasn't installed by them. Everyone says the same thing. It must be performed by the original installer.

I found an independent plumber who had no qualms to flush the unit. I spent less than $350 and he backs up the work. Send me a PM if you'd like details.

My minor issue with Navien is how the intake pipe will accumulate snow during very cold periods of winter. It is easy to brush out but it's a pain to discover your shower is cold and have to go outside in -20 to fix it.

Other than that, as long as you remember to clean the filter once in a while it has been great.

[Sliver]

I don't get what there is to like about these things. Was semi-interested until I read this thread. ~$350/year maintenance, higher upfront cost, randomly shutting off. My hot water tank just sits there working perfectly with no maintenance required.

[ken0042]

Originally Posted by Bean

My minor issue with Navien is how the intake pipe will accumulate snow during very cold periods of winter.

I had that issue with my regular tanked water heater. The installer put the input and exhaust too close together, so I had them come out and re-route the exhaust.

I have to agree with Sliver- seems like more of a pain that it's worth; with no cost savings. Also since going to a 50 gallon tank I've never had issues with all 4 of us having consecutive/simultaneous showers. Let alone the small amount a washing machine or dishwasher uses.

[Shazam]

Apparently it's the pre-2000 water heater tanks that were terrible. Anything made after 2000 were significantly more energy-efficient. Anything made these days are supposedly extremely efficient. I replaced mine about 4 years ago (50 gallon) and running out of hot water takes about 40-50 minutes via shower.

[Diemenz]

Had one, it was replaced after about a year with a tanked system. I was not a fan at all. The upstairs bathrooms would take about 2 minutes to get hot. The dishwasher was a joke as the initial cleaning requires hot water and it was more like room temp. Washing machine was also an issue when I did hot water washes.

I can see how in a small townhouse this could make sense but in a 3 floor house with the system in the basement and no recirculating it was terrible.

[afc wimbledon]

I have a 3 storey East Van old timer, box with a triangle on top, heaters in the basement bathroom on top floor, works fine endless hot water in a house with three teenagers is golden, even put a 110 gallon stock tank on the deck to use as a impromptu hot tub, keeps it toasty warm

[aaronck]

I have a new Rinnai in the house I purchased 2 years ago-(installed just before we moved in) I echo all the comments about the wait for hot water to reach the tap, and temperature not being that hot, and the requirement for a water softener to be installed in Calgary- I like the fact that I don't run out of hot water, but in general I'm not sure It's worth it, I'm not sure if this one failed that I would get another one-I would definitely look for one with a re circulation pump.

I just had the installer come and service it for the first time last week, it was $100 plus tax and I had him raise the temp for us(from 120- 130)

[Fuzz]

My opinion is that gas is cheap and water is not. I'd rather waste gas than water for money savings. And I'm not convinced my HWH wastes all that much.

[Shazam]

Originally Posted by Fuzz

My opinion is that gas is cheap and water is not. I'd rather waste gas than water for money savings. And I'm not convinced my HWH wastes all that much.

I turn off my furnace and turn off all the fireplace pilot lights when the weather gets warm. The HWH uses 1GJ of NG per month.

[DeluxeMoustache]

Originally Posted by Fuzz

My opinion is that gas is cheap and water is not. I'd rather waste gas than water for money savings. And I'm not convinced my HWH wastes all that much.

I was thinking about that.

Originally Posted by bc-chris

i like the fact that i'm not paying to keep a tank of water hot and i like that when we have company everyone can have a shower and we don't run out of water

Does it really work like this? Are you paying to heat the water, so long as you are heating your house?

Definitely you are adding heat at a much higher rate when you need the water. This is offset by not adding energy when you don’t need hot water. I have seen stats about 22 pct efficiency increase for water heating as a result

And you clearly are going to consume more water waiting for hot water. Travel time is the same, but hot water leaves the tank at time zero. Hot water leaves the tankless whenever it gets hot. And you may or may not be using that lukewarm water or throwing away the kJ it took to heat it.

How about that efficiency gain, where the heat goes, and what you are paying for.

Consider the overall energy balance.

- You maintain water at some temperature in a hot water tank.
- Your hot water tank radiates and loses heat in to the air around it.
- You use more gas to make up for the heat you are losing from the water, to maintain water Temp
- That hot water tank is inside.
- You are maintaining an internal temperature in your home.
- The heat you lose from the water tank goes in to the air in your house.
- Your furnace does not need to add the kJ of heat that are lost by the tank, because they are already going in to the house

What do you think? Am I missing something?

* I totally get the point about having unlimited water for showers. But you must be paying more to heat the extra water that you wouldn’t otherwise be using.

[afc wimbledon]

Its the unlimited water part I enjoy the most, it is cheaper but that is me comparing it to an old tank system, I have no doubt a newer tank would also be cheaper

[calgarywinning]

You can also maintain water tank systems of professional quality. They have anode rods which can be replaced as all the bad stuff will eat the rods instead of the tank. As the rods wear out the wear and tear goes to the tank. Probably runs about the same cost as running a boiler. Also, the water is insulated in the tank and you can hook up a holding tank. I'm still uncertain over the longterm which is best.

[zamler]

Originally Posted by Sliver

My hot water tank just sits there working perfectly with no maintenance required.

Water tanks do require maintenance of sorts they should be drained completely every year to get the crud out that accumulates.

[speede5]

I put in a power vent when our electric water heater started on fire 8 years ago. I wanted to go tankless but it was cost prohibitive and I got a brand new unit off a plumber friend for 500$ and installed it myself (plumber ran a gas line for $150).

The electric savings were close to $50 a month. Family of 5.

My unit rarely runs when I am not using water. I never hear it running unless there is demand. It probably comes on the odd time while I'm not around but it is really efficient. I thought it was screwed this winter as it started leaking, but it turned out to be the plastic drain valve cracked which I replaced with brass. I had a good look inside with a camera and the interior had a fair amount of build up but no corrosion. I'm sure it will be good for another 8 years.

The build up would be a much bigger issue in a tankless. The hardness of your water should definitely be a factor in switching. Also consider the water temp coming in. They can only raise the temperature so much, and in the winter my supply is quite cold. I haven't heard of any issues from the few friends I know who have these, but you want to make sure your unit can handle it.

A power venting unit is a real nice middle ground, and if you are already plumbed for a tak they are pretty much a drop in. There is only one exhaust vent that needs to be added as they get their combustion air from inside so you never have the vent issues either.

I have a high efficient furnace and I am always messing around with it's vent in the winter and never an issue with the water heater.